| As an interesting contrast China (which is also suffering fertility issues) just launched a new pro family/fertility campaign [1]. It's so weird how little coverage this issue receives in the West. Fertility will be one of the biggest factors in shaping our future, to say nothing of its more immediate impact on economic factors, retirement, and general social stability. I think the big issue is that we live so much longer than we're fertile that it masks the impact of fertility changes by ~60 years. So this makes many people not really appreciate what's happening. To give a toy example, imagine a world with a fertility rate of 1, where everybody reproduces at 20, and dies at 80: --- (100) Year 0: 100 births, 0 twenties, 0 forties, 0 sixties, 0 deaths (150) Year 20: 50 births, 100 twenties, 0 forties, 0 sixties, 0 deaths (175) Year 40: 25 births, 50 twenties, 100 forties, 0 sixties, 0 deaths (187) Year 60: 12 births, 25 twenties, 50 forties, 100 sixties, 0 deaths (93) Year 80: 6 births, 12 twenties, 25 forties, 50 sixties, 100 deaths (46) Year 100: 3 births, 6 twenties, 12 forties, 25 sixties, 50 deaths Year 120: 1 birth... --- Various observations: - Everything looks fine (if not great) until the first generation born from a high fertility generation starts to die. Somebody in year 20 saying there's a major fertility crisis would probably be considered eccentric. - A fertility rate of 'n' results in an n/2 ratio of younger:older. Fertility rate of 1 = 50% as many people in each succeeding generation that will be ultimately responsible for economically supporting the previous generation. - By observation 2 one could recreate the entire demographic distribution of year 0. If we assume a fertility rate of e.g. 4, then it would be a ratio of 4/2 younger people per older generation. So it would be: 100 births, 50 twenties, 25 forties, 12 sixties, and 6 deaths. - The effects are exponential with relation to our window of fertility, and not our life expectancy. From year 60 onward in the above sim, the population would drop by 50% every 20 years. All life expectancy does is add a longer period before you hit an equilibrium. - The minimum sustainable fertility rate is 2. This would, when equally distributed, be a society where 100% of women are having an average of 2 children each. It's unclear that anything like this is obtainable in our current economic and social models. [1] - https://www.globaltimes.cn/page/202305/1290693.shtml |